acidulated with hydrochloric acid, and boiled in a solution of soda,
then washed as before in clear water. Next they are chlorined by being
laid in a stone cistern containing a solution of chloride of lime and
allowed to remain a few hours. This operation requires great care in
the preparation of the chloride of lime, for if the smallest particle
of undissolved bleaching powder is allowed to come in contact with and
remain upon the cloth it is liable to produce holes. The goods are
then boiled for four or five hours in a solution of carbonate of soda,
after which they are washed. They are again chlorined as before and
washed. The long strips are finally scoured in hydrochloric acid,
washed, and well squeezed between metal rollers covered with cloth.
After squeezing and drying, the cloth, if required for printing, needs
no further operation, but if intended to be marketed in a white state,
it must be finished, that is, starched or calendered.

=Starching.= The starch is applied to the cloth by means of rollers
which dip into a vat containing the solution, while other rollers
remove the excess. Sometimes the cloth is artificially weighted with
fine clay or gypsum, the object being to render the cloth solid in
appearance.

=Calendering.= The cloth is now put through the calendering machine,
the object of which is to give a perfectly smooth and even surface,
and sometimes a superficial glaze; the common domestic smoothing iron
may be regarded as a form of a calendering utensil. The cloth is first
passed between the cylinders of a machine two, three, or four times,
according to the finish desired. The calender finishes may be classed
as dull, luster, glazed, watered or moire, and embossed. The calender
always flattens and imparts a luster to the cloth passed through it.
With considerable pressure between smooth rollers a soft, silky luster
is given by equal flattening of all the threads. By passing two folds
of the cloth at the same time between the rollers the threads of one
make an impression upon the other, and give a wiry appearance. The
iron rollers are sometimes made hollow for the purpose of admitting
steam or gas in order to give a glaze finish. Embossing is produced by
passing the cloth under heated metal rollers upon which are engraved
suitable patterns, the effect of which is the reproduction of the
pattern upon the surface of the cloth.

=Mercerizing.= This is a process of treating cotton yarn or fabrics
with